A ground-breaking new Irish study has given a cautious green light to using e-cigarettes as a cost-effective way to quit smoking.

The first official study in the EU by a member state to include e-cigarettes, in an analysis of smoking cessation tools, has found that they do help people stop smoking.

However, Dr Máirín Ryan, director of health technology assessment for the Health Information Quality Authority (HIQA), which conducted the study, cautioned that the long-term effects of e-cigarettes are not yet known.

Like methadone used to treat heroin addiction, the nicotine contained in e-cigarettes is still just as addictive as the nicotine in cigarettes.

However, the risk to health posed by nicotine consumed by "vaping" is much less than through actual smoking, she told the Irish Independent.

"There's no combustion and no tobacco so that means you avoid a lot of the toxins associated with smoking," she said.

The study, which used a relatively small sample of just 60 smokers, found they were twice as likely to stop smoking for good through vaping than not using any medication or smoking cessation aid.

The study revealed that close to a third of smokers who are trying to quit have used e-cigarettes to break the habit.

It also found that a rise in the use of e-cigarettes would cut €2.6m from the €40m the State spends each year to encourage people to quit smoking.

The 700-page study also found that the drug varenicline, which is sold under the brand name Chantix, is the single most effective medication to quit smoking and is more than two-and-a-half times as effective as quitting without drugs or other tools. Used alongside nicotine replacement therapy with such tools as nicotine replacement gum or sprays, it was found to be more than three-and-a-half times as effective as going "cold turkey".

"This report found that all publicly funded smoking cessation interventions can be considered clinically effective when compared with doing nothing and cost-effective when compared with unassisted quitting," Dr Ryan said.